Refinery process units, such as fluid catalytic cracking units, and other reactors and furnace-like equipment require, by their very nature, heat, wear and chemical resistant linings along portions of their interiors. The present art of ramming monolithic refractories into hexagonal-shaped metal mesh is well known.
Common practices in the field are to line reactors with hexagonal mesh (FIGS. 1–3) into which a refractory monolithic material is rammed while in a plastic, malleable state. Reactions in such materials, with or without the application of heat, cause a hardening of the material resulting in a lining in the wear areas capable of withstanding the environment encountered. In contrast to malleable state materials, it has long been known that pre-formed ceramic materials are more resistant to wear, erosion, and corrosion conditions than monolithic refractories. Ceramic tiles, though resistant to extreme conditions, are relatively brittle. As such they must be mounted to a reactor substrate lining with care. Mounting them gently, however, often impedes how securely the tiles are affixed to the lining. Prior art has resulted in tiles that are unreliable and which fail due to thermal cycling and other stresses which occur in service.
FIGS. 1, 2 and 3 illustrate the current practice of using malleable, non-preformed materials and injecting them into mesh. Referring to these figures, it can be seen that hexagonal mesh (Hexmetal) 10, which is typically ¾ to 1″ thick, is formed from metal strips 101 bent to form half-hexagonal shapes which are connected by clinches 102 punched from the metal strips 101 and bent over to secure two strips 101 together to form the hexagonal cells. Mesh 101 is preferably welded to substrate 302 via weld 215. Tabs 103 may be punched from metal strips 101 and help to secure the monolithic refractory into the cells after hardening. After filling of the cells, the monolithic refractory hardens by use of a setting agent or by application of heat to form a wear- and corrosion-resistance lining.
To the extent that any pre-formed tiles are used, tabs 103 may be of assistance in securing the tiles. The punching of tabs 103 leaves holes 104 in metal strips 101. These holes 104 can be used to secure pre-formed tiles to the interior of a reactor surface in place of the monolithic material.
Unfortunately, state of the art linings and the related techniques suffer from a number of drawbacks. These drawbacks include a relatively low mechanical stability and they often require very thick and heavy walls in order to provide the properties necessary to protect the reactor components. Another disadvantage of these prior art linings is the fact that it is generally difficult to remove individual elements or lining sections easily or non-destructively for replacement.
Finally, these prior art linings often are incapable of satisfying the ceramic property requirements associated with increasingly severe processes that result in ever increasing thermal and mechanical loads and stresses.